Are these books recommended? The first book is over two years old. Is it still relevant?

I am aware of course that Alfresco offers training courses. However those are not an option for me. I am a contractor focusing on ECM and CMS and would like to add Alfresco's products to my "portfolio". I do not have the time nor the money to attend an official Alfresco training course.

The best way is to just dive in, install it, and start working on the things that you need to know. This is not always easy or pain-free, but this is currently the best option.. I would suggest http://wiki.alfresco.com as a good source of information, but also join the community and get documentation from that spot. Alfresco is a big product so I would try to scope what you are interested in and start there.